Battery packs containing one or more batteries or cells are used in many applications including but not limited to telecommunications, grid, mobile, and/or any other suitable industries. In such applications, a plurality of battery packs are commonly connected in parallel to form a parallel battery string system. In such a system, a controller constrains operation of the battery strings based upon the current rating provided by the BMS. The current rating is typically determined by multiplying the rating of the individual battery strings by the number of operational strings which are connected in the system. Thus, a system level current limit for the power system can be easily determined and set for the system to operate within.
Due to the nature of a parallel-string energy storage system, individual strings can disconnect for various reasons. For example, individual strings may disconnect from the system due to over/under temperatures, over currents, over/under voltages, control failures, or similar. If individual strings disconnect and the power system is not given an updated current limit, the system will continue operating at the previously set current rating which can recharge/discharge the remaining strings above their design. In the case of a controls failure or a communications issue, the previously set current rating may lead to equipment damage and/or failure.
In view of the aforementioned issues, it is desirable to provide an improved system and method for protecting parallel-string energy storage systems from overcurrent conditions caused by a static current rating. Thus, the present disclosure is directed to a system and method for protecting parallel-string energy storage systems from overcurrent conditions by using dynamic voltage limit control.